Liquid crystal of an LCD does no itself emit light. Therefore it is common for a backlight module to be installed in an LCD device together with the LCD. The backlight module provides a uniform flat light source to enable the LCD to display images.
Referring to FIG. 8, this is an exploded, isometric view of a typical liquid crystal display. The liquid crystal display 10 includes a liquid crystal panel 190, and a backlight module 100 adjacent to an underside of the liquid crystal panel 190.
The backlight module 100 includes a first brightness enhancement film 110, a second brightness enhancement film 120, a diffusion film 130, a light guide plate (LGP) 140, a plurality of light emitting units 150, a reflector 170, and a frame 160. The first and second brightness enhancement films 110, 120, and the diffusion film 130 are arranged from top to bottom in that order. The frame 160 receives the three films 110, 120, 130, the LGP 140, the light emitting units 150, and the reflector 170. The frame 160 may be made of metal, plastic, or another suitable material. The light emitting units 150 are typically light emitting diodes (LEDs).
The LGP 140 includes a light incident surface 141, a light emission surface 142 substantially perpendicular to the light incident surface 141, and a bottom surface 143 opposite to the light emission surface 142. The light emitting units 150 are arranged adjacent to the light incident surface 141 of the LGP 140. The reflector 170 is located adjacent to the bottom surface 143 of the LGP 140. The diffusion film 130 is disposed adjacent to the light emission surface 142 of the LGP 140.
The liquid crystal display 10 is assembled by the following steps: firstly, the LGP 140 and the reflector 170 are received in the frame 160; subsequently, the light emitting units 150 are arranged in the frame 160 adjacent to the light incident surface 141 of the LGP 140; finally, the diffusion film 130, the second and first brightness enhancement films 120, 110, and the liquid crystal panel 190 are disposed in that order from bottom to top on the light emission surface 142 of the LGP 140.
The frame 160 is made of metal, plastic or another suitable material, and includes four enlarged corner portions for added strength (see FIG. 9). However, the liquid crystal display 10 may sustain great shock when it falls to the ground or is bumped. As a result, components of the liquid crystal display 10 are liable to be damaged. In particular, the liquid crystal panel 190 and the LGP 140 are liable to sustain damage.
What is needed, therefore, is a backlight module and a liquid crystal display employing the backlight module that can overcome the above-described deficiencies.